Question

What is the coefficient of X^2 in the expansion of (X +2)^3

Answer 1

With simple elements such as x and 2, it's worth learning special products:

(a+b)^3 = a^3 + 3a^2b + 3a^b^2 + b^3

Thus,

(x+2)^3 = x^3 + 3*2x^2) + 3(x)(2)^2 + 2^3

which simplifies to x^3 + 6x^2 + 12x + 8. The coeff. of x^2 is 6.

You could also use Pascal's Triangle to help you figure the coefficients.

Answer 2

the coefficient is 2 !! I guess, I learned this a lot of years ago, sorry